The first of a series of powerful earthquakes that hit Niigata Prefecture on Oct. 23 registered the strongest intensity of 7 on the Japanese seismic scale, equivalent to the 1995 Great Hanshin Earthquake that killed more than 6,400 people, the Meteorological Agency said Saturday.

The agency earlier said the initial quake, which jolted Niigata Prefecture at 5:56 p.m. Oct. 23 with a preliminary magnitude of 6.8 on the Richter scale, registered upper 6 at maximum.

However, the data the agency received a week later from the town of Kawaguchi showed a recorded intensity of 7 there at 5:56 p.m., it said, adding that an automatic data transmission system in the town had stopped functioning due to a power outage.

The Hanshin quake measuring a magnitude of 7.3 on the Richter scale hit Kobe and its vicinity in January 1995.